#include<stdio.h>
int main()
{
    int max();
    extern int a,b,c;
    printf("please enter three integer numbers\n");
    scanf("%d %d %d",&a,&b,&c);
    printf("max is %d\n",max());
    return 0;

}
int a,b,c;
int max()
{
    int m;
    m=a>b?a:b;
    if(c>m)m=c;
    return m;

}